Question 318667
A large software company gives job applicants a test of programming ability and the mean for that test has been 160 in the past. Twenty-five job applicants are randomly selected from one large university and they produce a mean score and standard deviation of 183 and 12, respectively. Use a 0.05 level of significance to test the claim that this sample comes from a population with a mean score greater than 160. 
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Ho: u = 160
Ha: u > 160
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mean of the sample: 183
std of the sample:12
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t(183) = (183-160)/[12/sqrt(25)] = 23/[2.4] = 9.58
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p-value = P(t > 9.58) = tcdf(9.58,1000 with df= 24) = approximately zero
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Conclusion: Since the p-value is less than 5%, reject Ho.
The test provides some evidence that the sample comes from
a population with a mean score greater than 160.
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Cheers,
Stan H.